Within the United States, 35 of the 50 states receive on average, at least two feet of snow per year. Snow can create hazards of slippery walks and driveways. Thus, clearing snow is a common occurrence during winter months in a majority of states with in the United States. Shoveling, even pushing a heavy snow blower, can cause sudden increase in blood pressure and heart rate, and the cold air can cause constriction of blood vessels and decrease oxygen to the heart. Thus, heart attacks become more of a risk during strenuous snow-clearing because blood pressure and heart rates spike while cold air constricts blood vessels and decreases the amount of oxygen received by the heart. When these factors combine and a person is not in peak health, shoveling can be a deadly activity.